Methods for well testing during wireline operations early in the exploratory life of a hydrocarbon bearing field are well established. Often the formation testing operation will identify formations of interest that deserve additional attention, but are too tight to deliver useful information in the limited amount of time available for a wireline operation. Usually these tight formations have permeabilities of 1 md or much less. Thus, a fracturing operation is required to create additional permeability in the formation so that a sufficient amount of reservoir fluid adequate for analysis is made available during the limited amount of time available for wireline operations.
A conventional fracturing operation is undertaken from the surface, and has two phases. In the first phase, a fracture is created by the expediency of exerting pressure that is greater than the existing formation/hydrostatic pressure against the face of the formation. This pressure is generated from pumps on the surface which force the fluid/slurry downhole to create the fractures. This additional pressure will cause the fracture to form, but the fracture will spontaneously close when the additional exerted pressure is removed.
To prevent fracture closure and the accompanying loss of fracture-induced improved permeability, it is standard practice to fill the fracture with proppant (i.e., the second phase of conventional fracturing operations). However, the proppant is supplied at the surface by mixing it into the fluid slurry being pumped downhole. Therefore, the overall process is inefficient and time-consuming.